We never had a kitchen microwave in the chemistry lab, but there was one in the adjacent office of our lab supervisor or in the break area in both the chemistry and biology labs at my former institution.  In my travels, in both the U.S. and other countries, there were usually kitchen microwaves in areas adjacent to the laboratory prep areas.

Needing to prepare solutions of non-flammable and non-hazardous materials such as soluble starch and polyvinyl alcohol for demonstrations and some limited classroom use, especially when traveling, I was able to prepare them quickly in the microwave.  My procedure was to make sure the initial volume was at 50% capacity of the container used (usually a Pyrex or similar beaker) and contents were at room temperature.  Initial heating was for 30 seconds, followed by opening the microwave and stirring with a non-metallic stirring rod, and then additional 30 second intervals, with stirring, until "solution" of the solute was evident.  If needed, additional 15 second heating intervals were used.  Solutions were never boiled or heated to boiling.  The procedure usually took several minutes.  Solutions had to be cooled before use.  This procedure was particularly useful when a soluble starch solution was needed for laboratory experiments in progress.

Should an individual desire to use this method, they should practice it to learn how the procedure works. I would never recommend a kitchen microwave for heating any flammable or hazardous material or for running any chemical reactions. 

David Katz